Automatic switch



July 9, 1929. F,-o R 1.720.342

AUTOMATIC SWITCH Filed June 21, 1928 Inusniur Herb??? F UbaTfgsZl Patented July 9, 1929.

UNITED STATES 1120.34.12 PATENT OFFICE.

HERBERT F. OBERGFELL, 0F RIVER FOREST, ILLTNOIS, ASSIGNOR T0 RESERVE HOLD- ING COMPANY, OF KANSAS CITY, MISSOURI, A CORPORATION OF DELAWARE.

AUTOMATIC SWITCH.

Application filed June 21, 1928.

This invention relates in general to switches of the type usedin automatic telephone systems, and it more specifically relates to an improved self-alining plunger for the nonnumerical line switch of the type commonly known as plunger line switches.

It is the principal object of this invention to provide a plunger of the self-alining type which is not only an improvement over the plunger disclosed in the patent to Newforth, No. 1,256,817, issued February 19, 1918, but is cheaply manufactured and which can be readily substituted for the plunger of the switch shown and described in my co-pending application, Serial No. 13,046, filed March 5, 1925.

The utility ofv the plunger of my invention will be fully appreciated when an understanding of the plunger construction has been had from the detailed description and the accompanying drawings. 1

In the sheet of drawings comprising Figs. 1, 2, and 3, Fig. 1 is a front view of the selfalining plunger of my invention. with its operating magnet, the main magnet of the line switch. In Fig. 1, the plunger is shown in its normal or unoperated position. Fig. 2 is also a front view, but it shows the plunger in its operated position. Fig. 3 is a crosssectional view taken along the line 3-3'of Fig. 2, and it has been drawn to an enlarged scale so that, the assembly might be more easily seen.

Referring in'detail to thefignres, it will be noted that the reference numeral 1 designates the main magnet of the switch. That magnet has two armatures, the bridge cut-0E armature 2 and'the pull-down or plunger armature 3. Those armatures are pivoted on the switch frame, not shown, at4. The function of the armature 2 is well known and, therefore, nothing further will be said about it. The function of armature 3 is obvious.

The right extremity of armature 3 is formed in a U. Each side of the U has an ear 5 which is bent downwards at right angles to the surface of the armature. Only one of the ears is visible in the drawings.

The plunger 6 is of the'general shape shown in the drawings, having the fan-tail 7 There is a hole in'the plunger at the apex of the fan, which is adaptedto receive the shaft 8 to which the plunger is rigidly staked. The

a shaft 8 is hollow to receive'the pivot pin 18. The endsof pin 8 areforced intoholes in the switch shaft 9.

Serial No. 287,153.

The ends of the arms-below the armature 3 are connected together by the coil spring 12.

The action of this spring keeps the otherends of the arms as close together as possible.' A projecting piece 13 on the fan-tail? acts as a spacer, holdingarms 10 and 11 a certain distance apart. The spacer 13 isformed as a part of the fan-tail, or web, it being bent over and upwards with respect to the position of the plunger in the drawings. The arms 10 and 11 are separated from the face of the fan by. the shoulder 19, Fig. 3, and are held in place by washer 14 whichis staked to shaft 8.

The arm 11 lies nearer to the plunger at the shaft 8, having been'put. on the shaft first, while arm 10 hasbeen so formed by bending that the end above armature 3 lies in the'same plane as arm 11.

To prevent the arms from rubbing the surface of the fan and binding, the fan is pro- 'vided with the ridge 15 which is a raised portion ofthe fan. It will be noted that the curbed edge of the fan is an arc of a circle 'whose center is the center of the pivot pin.

Theridge 15 has also been formed as an'arc of a circle with its centerooncentric with that of the fan edge, thus keeping the surface upon which the arms might rub, at a minimum.

The upper ends of the arms 10 and 11, are provided with. projections which are bent over and then inward, with respect to each other, so' as to form brackets for holding the roller bushings 16 and 17." These bushings roll upon the faces of the blade of the master .Theflower portion of 'the plunger -6 is formed like the plunger in 1ny"co-pending application for operating the springs ofthe line switch bank (not shown) I Referring particularly to Fig. 3, the mounting of the parts on the shaft 8 will be explained further. The shaft is made hollow to receive the pivot pin 18. Bushings 20, of insulating material, are tightly 'fitt-edwithin the hollow shaft to insulate it from the pivot pin 18. The plunger 6 is slipped over the left end of the shaft onto the shoulder 22 and against the shoulder 21. shoulder 22 are then bent over by staking to hold plunger 6 rigidly on shaft 8. Arm 11 and then arm 10 are slipped over the left end of the shaft, onto shoulder 23 and against shoulder 19. The washer 14 is then placed on the shaft, onto shoulder 24 and against shoulder 23. The staking operation is then performed on shoulder 24 to hold washer 14 in place. Arms 10 and 11 are free to rotate on the shoulder 23 of shaft 8 and are separated from the plunger 6 by the shoulder 19. 1 Referring particularly to Fig. 2, it will be assumed that the line switch is in use and that magnet 1 has been energized and has attracted its armatures 2 and 3 as shown.

When the pull-down armature 3 is attracted by magnet 1, it plunges the plunger 6 into the line switch bank to operate the contacts of and to connect the line associated with the line switch to an idle trunk leading to the second switch of the switch train. Inasmuch as it is the function of the master switch to keep the plungers of idle line switches of a. group opposite an idle trunk, the master switch will operate to move its shaft 9 to the position shown in Fig. 2 after plunge-r 6 has been plunged intothe bank.

Since the plunger is held firmly in the bank until released, the movement of shaft 9 will move arm 10 to the position shown in Fig. 2. The rotation of arm 10 about pivot 18 will store up tension in the spring 12. If shaft 9 should again be moved in the same direction, it will move arm 10 an additional amount.

When the line switch is released from the connection, the magnet 1 will deenergize, retracting its arinatures. The retraction of armature 3 pulls plunger 6 out of the switch bank. This leaves plunger 6 free to rotate about pin 18 under the action of spring 12 and plunger 6 will rotate in a counter clockwise direction to aline itself with plungers of other idle line switches, opposite an idle trunk.

Assuming that plunger 6 is in its operated position, having been plunged into any position of the switch bank except the first and tenth positions.

In this case the movement of the master switch shaft will move the arm 10 as described. But, when the shaft moves the idle wipers from the last position to the first position, shaft 9 moving ina clockwise direction, arm 10 will be restored and arm 11 will be rotated in a clockwisedirec-tion about pin 18. Therefore, when the plunger is removed from the bank, it will rotate in a clockwise direction about pin 18 to aline itself with the other idle plungers.

From the above description it will be seen by those skilledin the art, that I have produced a self-alining plunger which is simple in its construction and easily manufactured because the plunger and arms all pivot on one The edges of 7 pin and the spacer has been formed from the plunger itself. Not only that, but the possibility of the plunger becoming out of line with respect to the other plungers of the switches of the group and the master switch shaft is entirely eliminated, and the chance of the action of the plunger being faulty due to binding has been reduced to an absolute minimum.

Having thus described my invention, what I consider new and desire to have protected by Letters Patent is pointed out in the appended claims.

WVhat is claimed is: I

1. In an automatic switch, a pivoted plunger for closing contacts, said plunger operated by a magnet and moved about its pivot by a flanged shaft, a pair of arms pivoted on the same axis as the plunger, and a spring attached to one end of each arm on one side of the pivot point, said arms extendingsubstantially parallel on the other side of the pivot point and engaging the sides of said shaft;

2. In an automatic switch, a pivoted plunger for closing contacts, said plunger operated by a magnet and moved about its pivot by a flanged shaft, a pair of crossed arms pivoted at the point of crossing on the'same axis as the plunger, and a spring attached to one end of each arm on one side of the crossing-point, said arms extending substantially parallel on the other side of the crossing point and engaging the sides of said shaft.

3. In an automatic switch, a pivoted plunger for closing contacts, said plunger operated by a magnet and moved about its pivot by a flanged shaft, a pair of crossed arms pivoted at the crossing point on the same axis as the plunger, a spring attached to cooperating ends of said arms on one side of the crossing point, a web or fan-shaped member on said plunger, and an upwardly turned projecting piece on said web, said arms on the side of the crossing point opposite the spring held against said projecting piece by the spring and engaging the sides of said shaft.

4; In an automatic switch, a pin carrying a rotatable shaft, a contact-closing plunger rigidly staked on said shaft, said plunger operated by a magnet and rotated with said shaft aboutsaid pin by a flanged member, a pair of crossed armsrotatably mou'ntedon said shaft at the point of crossing, and a spring attached to cooperating ends of said arms on one side of said shaft, said arms on the other side of said shaft engaging the sides of said flanged member; V

5. In an automatic switch, a rotatable shaft, a contact-closing plunger rigidly staked on said shaft, said plunger operated by a magnet and rotated with said shaft by a flanged memher, a pair of crossed arms rotatably moved on sald shaft, a shoulder on said shaft separatmg said plunger from said arms, and a spring attached to cooperating ends of said arms on one side of the shaft, each of saidarms on the other side of said shaft engaging one side of said flange.

6. In an automatic switch, a rotatable shaft, a contact-closing plunger rigidly staked on said shaft, said plunger being fan-shaped at one end, operated by a magnet and rotated with said shaft by a flanged member, a pair of crossed arms rotatably mounted on said shaft at the crossing point, a shoulder on said shaft to prevent said arms from rubbing said plunger near said shaft, a ridge near the periphery of the fan-shaped end of the plunger to prevent said arms from rubbing the fanshaped surface, and a spring attached to said arms on one side of said shaft, each of said arms on the other side of said shaft engaging a different side of said flange and adapted to be rotated about said shaft in a different direction by said flanged member.

In witness whereof, I hereunto subscribe my name this 19th day of June, A. D. 1928.

HERBERT F. OBERGFELL. 

